The highly heterogeneous response of the same type of cancer (e.g., colon cancer) to a given anti-cancer compound in different patients is one of the most vexing and tragic problems of modern medicine. It is widely thought that human genetic and epigenetic diversity underlies much of the variation in response to chemotherapy. Thus, there is an ongoing effort to identify in the human population the molecular genetic correlates (i.e., molecular signatures) of cancer resistance and sensitivity to specific therapeutic agents. It is hoped that such efforts will ultimately enable physicians to predetermine the likelihood that a patient's cancer can be effectively treated with a particular anti-cancer compound.